<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://unpkg.com/vue"></script>
    <script >
        window.onload=function(){
            var app4 = new Vue({
                el: '#app-4',
                methods: {
                    addthing:function(){
                        this.todos.push({name:this.thing,done:false})
                    }
                    ,switchthing:function(index){
                        this.todos[index].done=!this.todos[index].done;
                    }
                },
                data:{
                    thing:null,
                    todos:[
                    {name:'吃饭',done:false},
                    {name:'睡觉',done:false},
                    {name:'哈哈哈',done:true}
                    ]
                }
                ,computed:{
                    done:function(){
                        var count=0;
                        for(var i=0;i<this.todos.length;i++){
                            if(!this.todos[i].done){
                                count++;
                            }
                        }
                        return count;
                    }
                }
            })
        }
    </script>
    <style>
        .del{text-decoration: line-through}
    </style>
</head>
<body>
<div id="app-4">
    <h2>TODO LIST</h2>
    <input type="text" v-model="thing">

    <button v-on:click="addthing">添加</button>
    <div v-for="(todo,index) in todos" >
        <input type="checkbox" v-bind:click="todo.done" v-on:click="switchthing(index)" >
        {{index}}.<span v-bind:class="{del:todo.done}">{{todo.name}}</span>
</div>
    总共{{todos.length}}个事项,{{done}}个已完成，{{todos.length-done}}个未完成
</div>
</body>
</html>